
At birth, humans have about 30,000 hair cells, which can be damaged by infections, ageing, genetic diseases, loud noise or treatment with certain drugs. In most cases, damaged hair cells do not regrow in mature humans. But recent research has kindled hope that nerve deafness may one day be curable. A team of scientists led by John Brigande at the Oregon Health and Science University, in Portland showed that implanting a gene known as Atoh1 into the inner ear of a mouse embryo coaxed non-sensory cells to become hair cells.

